## Summary
Server-side movement throttle that prevents speed hacking while accurately identifying cheaters with detection of lagging connections.
**Key features:**
- Credit buffer (200ms) absorbs timing jitter from legitimate players
- Movement queue handles larger bursts, draining at proper game-tick intervals
- RTT measurement distinguishes network lag from speed hacks
- Queue depth detection catches ACK-throttled speed hacks (going straight)
## How It Works
**Throttle** (prevention): Movements arriving too early either consume credit or get queued. The queue drains at
correct intervals, so speed hackers can't move faster regardless of what they send.
**Detection** (identification): Combines multiple signals to identify cheaters:
| Signal | What it catches |
|--------|-----------------|
| Queue depth ≥4 sustained | ACK-throttled speed hacks (client limits unacked moves to 5) |
| Movement rate >1.05x | Direction-change speed hacks where timing is visible |
| Stable RTT + high queue | Eliminates false positives from laggy players |
**RTT-Aware Logic:**
- Probes only sent to players actively moving (event-driven, not global loop)
- Stable low-latency + problems = suspicious
- Unstable/high-latency + problems = probably just lag, throttle handles it
## Configuration
```json
{
"movementThrottle.maxCredit": 200,
"movementThrottle.softQueueLimit": 6,
"movementThrottle.hardQueueLimit": 10,
"movementThrottle.debugLogging": false
}
```
> [!IMPORTANT]
> **Breaking Changes**
> - DecodePacket and EncodePacket delegates replaced with IClientEncryption interface
> - NetState.Connection (Socket) replaced with internal RingSocket management
> - NetState.RecvPipe and NetState.SendPipe removed (buffers managed internally)
## Summary
Upgrades the networking stack from PollGroup-based I/O to io_uring, significantly improving I/O performance on Linux.
This also adds native client encryption support for encrypted UO clients.
## Major Changes
io_uring Networking Architecture
- Replaced PollGroup with IORingGroup for async socket I/O operations
- Removed Pipe.cs (mirrored ring buffer) and TcpServer.cs in favor of RingSocketManager
- Added NetState.Network.cs - centralized network infrastructure handling accept, recv, send, and disconnect
completions
- Added SocketHelper.cs - platform-specific socket utilities for raw socket handle operations (getpeername,
getsockname)
- Buffer management now handled by RingSocketManager with configurable slab allocation
### Client Encryption Support
- Added full encryption stack in Network/Encryption/:
- EncryptionConfig.cs - configurable encryption modes (None, Unencrypted, Encrypted, Both)
- EncryptionManager.cs - encryption detection and initialization for login/game packets
- LoginEncryption.cs - handles login packet encryption with version-derived keys
- GameEncryption.cs - handles game server encryption using Twofish
- TwofishEngine.cs - optimized Twofish block cipher implementation
- LoginKeys.cs - encryption key table for client versions
- IClientEncryption.cs - interface for client encryption implementations
### NetState Improvements
- Replaced Socket Connection with RingSocket _socket for managed socket lifecycle
- Changed from GCHandle polling to event-based completion processing
- Disconnect handling now properly waits for pending sends to flush
- Simplified connecting socket management using lazy queue removal
### Configuration
- New settings: network.encryptionMode and network.encryptionDebug
- Encryption mode flags: Unencrypted, Encrypted, or Both
### Dependencies
- Replaced PollGroup NuGet package with IORingGroup
- Linux requires liburing-dev / liburing-devel package
### Test plan
- Verify server starts and accepts connections on Linux with io_uring
- Verify server starts and accepts connections on Windows (fallback to IOCP)
- Test unencrypted client connections (ClassicUO with encryption disabled)
- Test encrypted client connections if available
- Verify graceful disconnect flushes pending data
- Confirm CI builds pass on all target platforms
## Summary
- Adds proper Latin1 encoding support, replacing CP1252 usage throughout the codebase
- Adds specialized, optimized string decoding methods with safe string filtering for each encoding type
- Filters invalid Unicode characters (C0/C1 control codes, non-characters) by removal rather than replacement since
the UO client renders nothing for these characters
- Fixes UTF-16 null terminator position handling to correctly advance by 2 bytes
## Changes
TextEncoding.cs
- Added SearchValues-based invalid byte/char detection for efficient filtering
- Added encoding-specific GetString methods: GetStringAscii, GetStringLatin1, GetStringUtf8, GetStringBigUni,
GetStringLittleUni
- Each method supports a safeString parameter for filtering invalid characters
- Little-endian UTF-16 uses direct memory cast for zero-copy decoding on LE systems
- Invalid characters are removed (not replaced with U+FFFD) since the client renders nothing for them
SpanReader.cs
- Added ReadLatin1() and ReadLatin1Safe() methods
- Rewrote encoding-specific read methods to use optimized TextEncoding.GetString* methods
- Fixed UTF-16 null terminator handling: position now correctly advances by byteLength (2) instead of 1
SpanWriter.cs
- Added WriteLatin1 and WriteLatin1Null methods
## Packet Updates
- Updated all packet code to use Latin1 encoding instead of CP1252
- Affected: account packets, equipment packets, menu packets, message packets, mobile packets, player packets, secure
trade packets, vendor packets, gump packets, book packets, mahjong packets
## Filtering Behavior
Invalid characters filtered in safe mode:
```
┌───────────────┬────────────────────────┐
│ Range │ Description │
├───────────────┼────────────────────────┤
│ 0x00-0x1F │ C0 control codes │
├───────────────┼────────────────────────┤
│ 0x7F │ DEL │
├───────────────┼────────────────────────┤
│ 0x80-0x9F │ C1 control codes │
├───────────────┼────────────────────────┤
│ 0xFFFE-0xFFFF │ Unicode non-characters │
└───────────────┴────────────────────────┘
```
Note: Surrogate pairs (0xD800-0xDFFF) are not filtered because proper validation requires context checking for paired
vs unpaired surrogates. The UO client renders nothing for these anyway.
## Test Plan
- All 631 Server.Tests pass
- Verified client rendering behavior using TestUnicodeGump command (pages 1-5)
- Confirmed U+FFFD, unpaired surrogates, and non-characters all render as blank in client
- Verified Latin1 characters (0xA0-0xFF) display correctly
- Verified C1 control codes (0x80-0x9F) are filtered and don't display
### Summary
- Create BitMask256 struct with scalar operations (benchmarks showed AVX2 vectorization provides no benefit for this size)
- Refactor Map.cs to use BitMask256 for full Z range support (-128 to 127)
- Remove SectorSpawnCache struct, use BitMask256 directly in manager
- Update tests to use BitMask256 directly
- Remove unused test assertions for old 64-bit behavior
### Summary
- Adds CanSpawnMobile(x, y, minZ, maxZ, canSwim, cantWalk, out spawnZ) overload for finding spawn surfaces within a Z range
- Adds CanSpawnItem(x, y, minZ, maxZ, out spawnZ) for item spawning with Surface+Impassable support (tables, furniture)
- Uses bitmask optimization inspired by Item.DropToWorld's m_OpenSlots pattern for O(1) surface/blocker checks
- HomeRange spawners now use surface detection to set proper Z bounds
### Key Changes
Map.cs:
- CanSpawnMobile with Z-range finds lowest valid surface for mobiles
- CanSpawnItem with Z-range finds lowest valid surface for items (including tables)
- CanFitItem for point-check item placement on Surface+Impassable tiles
- Bitmask approach eliminates nested loops and stackalloc arrays
Spawners:
- Simplified GetSpawnPosition using new Z-range methods
- HomeRange setter detects surface below spawner for proper Z bounds
- Consistent handling for mobiles and items
### Bug Fixes
- Water tiles (Impassable | Wet) no longer block swimming mobs
- Items can now spawn on tables/furniture (Surface+Impassable)
### Test Plan
- Run dotnet test - 631 tests pass
- Manual testing: multi-story spawning, water mobs, item spawning on tables
- Verify HomeRange spawner movement shifts bounds correctly
### Summary
Adds `XInRangeByDistance` and `XInBoundsByDistance` methods to `Map.cs`:
**Item Distance Enumeration:**
```cs
ItemDistanceEnumerable<Item> GetItemsInRangeByDistance(Point3D p);
ItemDistanceEnumerable<Item> GetItemsInRangeByDistance(Point3D p, int range);
ItemDistanceEnumerable<T> GetItemsInRangeByDistance<T>(Point3D p) where T : Item;
ItemDistanceEnumerable<T> GetItemsInRangeByDistance<T>(Point3D p, int range) where T : Item;
ItemDistanceEnumerable<Item> GetItemsInRangeByDistance(Point2D p);
ItemDistanceEnumerable<Item> GetItemsInRangeByDistance(Point2D p, int range);
ItemDistanceEnumerable<T> GetItemsInRangeByDistance<T>(Point2D p) where T : Item;
ItemDistanceEnumerable<T> GetItemsInRangeByDistance<T>(Point2D p, int range) where T : Item;
ItemDistanceEnumerable<Item> GetItemsInRangeByDistance(int x, int y, int range);
ItemDistanceEnumerable<T> GetItemsInRangeByDistance<T>(int x, int y, int range) where T : Item;
ItemDistanceEnumerable<Item> GetItemsInBoundsByDistance(Rectangle2D bounds, , bool makeBoundsInclusive = false);
ItemDistanceEnumerable<T> GetItemsInBoundsByDistance<T>(Rectangle2D bounds, bool makeBoundsInclusive = false) where T : Item;
```
**Mobile Distance Enumeration:**
```cs
MobileDistanceEnumerable<Mobile> GetMobilesInRangeByDistance(Point3D p);
MobileDistanceEnumerable<Mobile> GetMobilesInRangeByDistance(Point3D p, int range);
MobileDistanceEnumerable<T> GetMobilesInRangeByDistance<T>(Point3D p) where T : Mobile;
MobileDistanceEnumerable<T> GetMobilesInRangeByDistance<T>(Point3D p, int range) where T : Mobile;
MobileDistanceEnumerable<Mobile> GetMobilesInRangeByDistance(Point2D p);
MobileDistanceEnumerable<Mobile> GetMobilesInRangeByDistance(Point2D p, int range);
MobileDistanceEnumerable<T> GetMobilesInRangeByDistance<T>(Point2D p) where T : Mobile;
MobileDistanceEnumerable<T> GetMobilesInRangeByDistance<T>(Point2D p, int range) where T : Mobile;
MobileDistanceEnumerable<Mobile> GetMobilesInRangeByDistance(int x, int y, int range);
MobileDistanceEnumerable<T> GetMobilesInRangeByDistance<T>(int x, int y, int range) where T : Mobile;
MobileDistanceEnumerable<Mobile> GetMobilesInBoundsByDistance(Rectangle2D bounds, bool makeBoundsInclusive = false);
MobileDistanceEnumerable<T> GetMobilesInBoundsByDistance<T>(Rectangle2D bounds, bool makeBoundsInclusive = false) where T : Mobile;
```
**Client Distance Enumeration:**
```cs
ClientDistanceEnumerable GetClientsInRangeByDistance(Point3D p);
ClientDistanceEnumerable GetClientsInRangeByDistance(Point3D p, int range);
ClientDistanceEnumerable GetClientsInRangeByDistance(Point2D p);
ClientDistanceEnumerable GetClientsInRangeByDistance(Point2D p, int range);
ClientDistanceEnumerable GetClientsInRangeByDistance(int x, int y, int range);
ClientDistanceEnumerable GetClientsInBoundsByDistance(Rectangle2D bounds, bool makeBoundsInclusive = false);
```
**Example Usage:**
How to use `minDistance` to terminate early when all subsequent mobiles in the iteration will be at an increasing min distance.
```csharp
var playerLocation = player.Location;
const int maxRange = 100;
const int maxMobiles = 12;
var closestMobiles = new SortedSet<Mobile>(Comparer<Mobile>.Create((x, y) =>
{
var distX = x.GetDistanceToSqrt(playerLocation);
var distY = y.GetDistanceToSqrt(playerLocation);
int result = distX.CompareTo(distY);
if (result == 0)
{
result = (x?.Serial ?? Serial.MinusOne).CompareTo(y?.Serial ?? Serial.MinusOne);
}
return result;
}));
int lastMinDistance = 0;
foreach (var (mobile, minDistance) in map.GetMobilesInRangeByDistance(playerLocation, maxRange))
{
// Stop if we have enough and distance starts increasing
if (closestMobiles.Count >= maxMobiles && minDistance > lastMinDistance)
{
break;
}
closestMobiles.Add(mobile);
lastMinDistance = minDistance;
}
// Results are already ordered by proximity
foreach (var mobile in closestMobiles)
{
var actualDistance = mobile.GetDistanceToSqrt(playerLocation);
Console.WriteLine($"{mobile.Name}: ActualDist={actualDistance:F2}");
}
```
> [!IMPORTANT]
> **Dev Note:** This is an **important** patch as the bug could lead to major issues like:
> * Multis/Players disappearing from view or not being counted during game logic.
> * World processes (e.g., area checks, targeting) failing to detect entities correctly.
> * General stability and correctness concerns for core map functionality.
>
> **Important Breaking Change**: Multis now properly use the map link list. This means modifying a multi while iterating will cause the server to crash. The crash _is expected_. Please modify/fix code accordingly to create a list using `PooledRefQueue` or `PooledRefList` instead of moving/deleting multis while inside the foreach.
### Summary
* Fixes a bug where deleting/moving a multi (boat/house) in some circumstances can use undefined behavior due to unsafe changes to List<BaseMulti>
* Fixes a bug where Multis may not be considered while searching due to a bug causing the sector search to end early.
### Summary
* Bumps to .NET 9 with updated dependencies
* Comparing a value type against null is no longer allowed
* CI/CD now uses the version specified in global.json
* Serialization generator updated to .NET 9 with bug fixes, fixes to turkish language, and parallelization
### Summary
Fixes a few minor issues with timers:
- Timer.Delay and Timer.Interval was not reflecting the actual tick time (aligned to the next 8ms)
- Negative delay values were causing a crash when DateTime.Now - delay was below DateTime.MinValue
- Timer.Next now reflects the correct wall clock tick time based on the adjusted Delay.
- Timer.Next is not assigned when the timer is started. This was important for timers that were created, but started later.
### Summary
- `GenericEntityPersistence` is now a type of `GenericPersistence`. This allows developers to serialize both entities and non-entities in the same system. 🎉
- Each `SerializationThreadWorker` now allocates 1MB of heap for serialization _permanently_. If more memory is needed, that thread will double it's memory, not to exceed increments of 64MB.
- Several bugs with serialization introduced with the pure MMF implementation have been fixed.
- `BinaryFileReader` has been added back. 🎉
- Adds `world.useMultithreadedSaves` to allow disabling threaded saves.
> [!IMPORTANT]
> **Developer Note**
> The split file serialization has been deprecated and is no longer used. We have effectively gone back to the same file writing we had before the pure MMF implementation.
> [!Important]
> **Developer Note**
> This code change will **completely move gumps out of the core**
### Summary
- Adds `GetGumps()` convenience which exposes methods to Find/Close/Send multiple gumps. This helper is a performance improvement by eliminating the Dictionary<Player, List> lookup for gumps.
### Summary
* Added World.NewVirtual for creating virtual serial numbers
* Reserved range 0x7EEEEEEE to 0x7FFFFFFF for virtual serials
* Hair and Facial hair (for mobiles) now use virtual serials instead of FakeSerial() functions
* Consolidated virtual hair to a single `VirtualHairInfo` class.
Corpse hair and facial hair now persists across save/load and hair and facial hair no longer teleport to newest corpse.
## Summary
- Removes allocation of a `List<ContextMenuEntry>` every time a context menu is created.
- Moves packet/context menu creation logic out of the core
- Fixes tame entry
## BREAKING CHANGE
> [!Important]
> **Developer Note**
> ```cs
> public virtual void GetContextMenuEntries(Mobile from, List<ContextMenuEntry> list)
> ```
> and similar functions changed to
> ```cs
> public virtual void GetContextMenuEntries(Mobile from, ref PooledRefList<ContextMenuEntry> list)
> ```
### Summary
Updates the serialization strategy to use `MemoryMappedFile` instead of thick buffers. This has the benefit of being on-par with the current implementation (based on hardware/OS), however won't incur the double-memory issue.
> [!Important]
> **Developer Note**
> The `BinaryFileWriter` and `BinaryFileReader` has been removed in favor of `MemoryMapFileWriter` and `UnmanagedDataReader`
### Summary
- Generalizes the On/Off toggle items concept
- Updates the OnOffGump so it is static
- Standardizes OnOff items so they can be used by staff
### Notes
Decided to not fix#1417 because it is not clear that the clilocs or errors are for that purpose. Can't test this on OSI anyways.
> [!Note]
> **Developer Note**
> Now developers will only need to build/run the Application project instead of everything.
> When adding new projects, make sure to:
> 1. Add a reference to that project in the Application project.
> 2. Add the dll file to the Distribution/Data/assemblies.json file
### Summary
- Adds an application project
- Consolidates process restarts to use `Core.Kill(true)`
- Removes some old messaging, for example processor optimization
- Fixes missing build cleanup
> [!Warning]
> Users on Linux/OSX will need to follow the Readme
> and make sure `libdeflate` is properly installed
> [!Note]
> **Developer Note**
> The API for compression has changed. Use `Deflate.Standard` for the same functionality.
### Summary
* Replaces Zlib with LibDeflate for a 50% performance improvement!
* Adds MacOS 14 to properly test Arm64
> [!CAUTION]
> **BREAKING CHANGE**
> Removed `OrderdHashSet` and `PooledOrderedHashSet` due to bugs.
> [!NOTE]
> **Developer Note**
> The OrderedSet is not a full data structure. It is not particularly efficient. Pull Requests are welcome for a better implementation, especially if it ends up supporting `ISet<T>` and `IReadOnlySet<T>`
## Summary
The ordered hash set was buggy. It's kind of painful to implement, so for now, I added a simple `OrderedSet` to suffice for gumps. Please reach out if this causes disruption!
### Summary
* Unifies reading UOP File indexes
* Adds ArtData file reader to get graphic bounds
* Automatically generates Bounds.bin from art file if missing
* Adds [GenBounds command to regenerate the bounds.bin file. Useful for when the art file changes.
